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The definitive guide to a 14 bolt swap (14BFF)

Discussion in 'The Garage' started by zakk, Jul 31, 2003.

  1. zakk

    zakk 1/2 ton status

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    The 14B swap is any easy and bulletproof upgrade to any vehicle. The greatness that is the 14 Bolt Full-Floater (Forthwith known as 14BFF) axle is we documented. It is so strong, and so cheap to purchase, rebuild, and upgrade that there are more than a few Ford's and Jeep's that run this monstrosity of an axle.

    To convert your 1/2 vehicle to 3/4 or 1 ton, you will need to find a 14BFF. Prices will vary from $0 - $300 for the unit, depending on your part of the world you call home. Most agree that $100-200 for a good unit is reasonable.

    Where do you find such an item? A junkyard, your neighbor's rig in his driveway (they are that common), or Salvage shops. There are many to choose from but we will assume you will be looking for a pre-AAM 14BFF (70's-80's) for this article.

    Variations of the 14BFF:

    K30,C30: narrower spring perches that will have to be rewelded, 2WD versions will also need new shock mounts. *Pre 1973 vehicles: This is a direct swap in, with the above mentioned notes (Beast3888)

    K20,C20: The K20 is a bolt in for post 1973 Rigs. Get the 8 lug conversion pieces for the front while you are at it. C20 will only need the shock tabs reworked

    Van 14BFF: The most desirable version. Specs differ depending on the year, but they are wider than a truck 14BFF so your track width will be the same (or closer to it)

    Gear ratios are between 3.73 and 4.56, with 4.10 being the most popular by far. A Deee-troit locker is the only available locker for the unit, and is substantially cheaper than any other locker out there. In addition, the strength of the 14BFF and the Deee-troit = bomb proof, IMHO. I don't carry spare anything for my 14BFF (which is equipped with a Deee-troit, also) save a driveline u-joint.

    Swapping the Unit it:


    If you were lucky enough to get a K20 14BFF: remove rear drive line, disconnect e-brake, remove axle, install new axle

    If you got any other 14BFF, you will most likely need to reweld the spring perches. IMHO, this should be done by a well trained welder. A professional if you can find one. Now is also the time to look at making any pinion angle adjustments.

    To remount the shocks, use your imagination. What I did won't work for 95% of you, so I won't even bother. As your having your spring pads rewelded, talk to your welder about some simple mounting tabs.

    To utilize your existing (stock) driveline, a conversion driveline u-joint must be used. Napa #348 u-joint is needed if you are replacing a 12 bolt, a Napa #447 is needed if you are replacing a 10 bolt.(Bowtiered & Beast388). A good driveline shop will be able to help you on this, or call Steve at South Bay Drive Line (408-995-6000) who seems to have every U-joint memorized and is cheaper than most mail order outfits. Tell him Phat zakk sent you. He'll then know your working on a Blazer of some sort.

    E-brakes are on a case by case basis. Mine work, but they aren't as tight as they used to be. Adjusting them is a fo-sho!

    Other issues to consider:
    The 14BFF is also affectionately known as the land anchor. while doing your swap it is a good idea to lop off 1" of the lower lip. this leaves well over .3" which is plenty of metal. Some have gone as far to make the 14BFF a 13BFF and turn down the ring gear and then plate the bottom. Remember: Ground Clearance: every 1/4" counts!.
    Also, the 14BFF is an 8 lug axle. It can be converted by use of adapters (one company is Echobit.com) to make it 6 lug, or you can swap 3/4 outers from a K20. You deiced what is best for you.

    And with that, I'm going to treat myself to a frosty Diet Coke. Good luck.[​IMG]
     
  2. Z3PR

    Z3PR Banned

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    Thanks for the write up /forums/images/graemlins/thumb.gif I'm sure it'll help out alot of people who are intrested in this mod. /forums/images/graemlins/thumb.gif
     
  3. big pappa b

    big pappa b 3/4 ton status

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    Thanks Zakk...you must have been reading my mind /forums/images/graemlins/thumb.gif

    Now can you do one for a D60 swap /forums/images/graemlins/ignore.gif /forums/images/graemlins/rolleyes.gif /forums/images/graemlins/rolleyes.gif
     
  4. zakk

    zakk 1/2 ton status

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    [ QUOTE ]
    Thanks Zakk...you must have been reading my mind /forums/images/graemlins/thumb.gif

    Now can you do one for a D60 swap /forums/images/graemlins/ignore.gif /forums/images/graemlins/rolleyes.gif /forums/images/graemlins/rolleyes.gif

    [/ QUOTE ]

    I haven't even finished my front Diet Coke!

    i think there is one, to be honest....
     
  5. zakk

    zakk 1/2 ton status

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    now that i actually think about it, a D60 swaps right in! all you need is a steering block (assuming you have a 4-6" lift) and new u-bolts. Brakelines hook right up (or alteast mine did, and all Dana axles use a standard driveline 1310 u-joint so there your driveline and yoke stays the same.

    in some cases, your front driveline might need to be shortened do to the pinion "length" of the D60 compared to the D44. i don't know the exact measurment.

    D60's are also 8 lug, so you save the cost of converting your D44 or 10B front to 3/4 ton 8 lug stuff.
     
  6. Beast388

    Beast388 1/2 ton status

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    zakk, to add to your uber-definitive 14BFF swap article, the Napa #348 u-joint is needed if you are replacing a 12 bolt, a Napa #447 is needed if you are replacing a 10 bolt. /forums/images/graemlins/thumb.gif

    K20 14BFF's are bolt in for 73-up trucks. Those of us with '72 and older will need to move perches (as I had to do) or find a 1-ton 14BFF.

    Great Write-up! /forums/images/graemlins/thumb.gif /forums/images/graemlins/thumb.gif
     
  7. zakk

    zakk 1/2 ton status

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    credit where credit is due /forums/images/graemlins/thumb.gif
     
  8. Emmettology 101

    Emmettology 101 3/4 ton status

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    I believe there is a spool available out there for a 14FF.. Sandy Cone I believe has one as well as someone else i think...
     
  9. zakk

    zakk 1/2 ton status

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    got a link?
     
  10. Lance

    Lance 1/2 ton status

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    Not to split hairs, but my stock d-shaft ('90 Jimmy) takes a 3r u-joint, not the more popular 1310/1330/1350 units you find. I searched around and couldn't find one through Spicer, Neapco, NAPA at the time. I had one (actually several) made at Birmingham Leaf Spring. Just a point some people may want to be aware of before undertaking the swap. Not a big deal but could stall a project by a few weeks.

    I searched on google to see if a part number for this converion exists, but wasn't able to come up with anything.
     
  11. tRustyK5

    tRustyK5 Big meanie Staff Member Super Moderator GMOTM Winner Author

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    I thought the one from Sandy Cone was a custom unit designed for 46 spline axles? /forums/images/graemlins/1zhelp.gif

    Rene
     
  12. Emmettology 101

    Emmettology 101 3/4 ton status

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  13. BurbLover

    BurbLover 1/2 ton status

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    Zakk,

    I'd like to say thank you very much for pretty much making this issue an idiot proof one for me. I have now added this to my Favorites as I'm sure I'll look at this quite often. I ssen to be loosing my memory in my old age /forums/images/graemlins/grin.gif

    Anyway, I'm sure your work in writing this article will do alot for any other mechanically challenged people like myself /forums/images/graemlins/thumb.gif

    /forums/images/graemlins/burb.gif /forums/images/graemlins/k5.gif
     
  14. Jonny-K5

    Jonny-K5 1/2 ton status

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    [ QUOTE ]
    Gear ratios are between 3.73 and 4.56, with 4.10 being the most popular by far.

    [/ QUOTE ]
    i have a 14bff out of a 76 k30 camper special sitting in my back yard. just went out and turned the wheel to figure out what the gear ratio was. i got a little over two revolutions on the pinion yoke with one rev of the tire. whats the lowested the 14 came with? unless im counting wrong, thats way less than 3.73
     
  15. FWP

    FWP CRS

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    Good write-up. You may want to add that a detroit will not fit a limited slip carrier, so if you plan on a detroit, find an axle with open diff.....
     
  16. Z3PR

    Z3PR Banned

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    [ QUOTE ]
    Good write-up. You may want to add that a detroit will not fit a limited slip carrier, so if you plan on a detroit, find an axle with open diff.....

    [/ QUOTE ] Good point, but also add how to tell the difference between a open carrier and limited slip, for those who don't know.
     
  17. Shaggy

    Shaggy 3/4 ton status

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    <font color="green"> Good write up! One thing to change - The K30 spring perches are wrong also and need to be redone, they are backwards from the ones that we need. </font>
     
  18. ChevyHuny

    ChevyHuny 1/2 ton status

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    Thanks for taking the time to do all of that. I am sure it will be really helpful. /forums/images/graemlins/smile.gif
     
  19. Greg72

    Greg72 "Might As Well..." Staff Member Super Moderator

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    Zakk,

    Maybe list the actual spring perch widths?

    I think the relevant ones are 42.5" (for almost everyone)....and 40" for the 1st Gen guys.

    Also, POFF wrote up a really nice document about not only the 14BFF swap but also 8-Lug front converions too. He never posted it on CK5, but had offered it to anyone who asked him via email. I got a copy and though it was well written. It had the complete procedures, as well as recommended tools, and parts sources for the small parts you'd need. Might be worth checking out if you're TRULY going to be "THE MAN" who writes the definitive 14BFF swap page.


    BTW -&gt; Mad amounts of this /forums/images/graemlins/thumb.gif for even trying to do a project like this one!
     
  20. Shaggy

    Shaggy 3/4 ton status

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    <font color="green"> I thought of something else that you can add, but it will take some research. The castings for the center chunk on the 14b changed at some point, the later ones seem to be thicker on the bottom. Mine is from an 87 and it doesn't have a 1" lip on the bottom, it's only like 1/2", so I know that they changed at some point. </font>
     

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